The Hematology Research Training Program at the University of Pennsylvania was established in 1978 and is currently in its 19th year of funding, the last four of which have been under the current principal investigator, Lawrence Brass. Throughout that time, the goal has been to help top candidates with an interest in the broadly-defined disciplines of hematology and, more recently, vascular biology to prepare themselves for academic careers in which their scientific training in laboratories could be applied to either laboratory or clinical research. During the first 19 years of funding, 70 postdoctoral trainees and one pre-doctoral trainee have been supported for work in 33 different laboratories: 57 M.D., 9 M.D.-Ph.D. and 4 Ph.D. Twenty of the trainees were women, 51 were men. Of the 64 trainees who have completed training to date, 41 (64%) hold full-time appointments at an academic institution and are engaged in either laboratory (22%) or clinical (42%) research. An additional 7 (11%) are engaged primarily in clinical practice, but have university appointments and participate in clinical research projects and teaching part-time. The remaining 25% are either not working for a variety of reasons (5%), employed in industry (3%) or engaged in full time private practice (17%). Approximately half of our former trainees have extramural research funding with direct costs in the current year exceeding $7 million. Graduates of this program hold appointments at 21 institutions around the United States, including the University of Pennsylvania, Harvard and the NIH. Among the program graduates there are currently 3 full professors, 11 associated professors, 20 assistant professors and 4 instructors. This proposal provides follow-up information on all of the trainees since the inception of the grant and describes how the program has evolved during the past two decades. Based on the success of the training program to date, the availability of additional strong candidates, and the growth of the faculty and programs in hematology and vascular biology, this proposal also makes the case for an increase in funding from the current 5 M.D., M.D.-Ph.D. and Ph.D. postdoctoral positions per year to 8 per year.